cells & tissues - bfhsemory · 2018-08-31 · cells ⦿ ribosomes very large enzymes • made...
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CELLS & TISSUES
Molecules of LifeChapter 2
MOLECULES OF LIFE⦿ Carbohydrates
◼ “Saccharides” – sugar and starch molecules◼ Simple Carbs – made of one or two subunits
• Monosaccharide - glucose • Disaccharide – made of 2 monosaccharides -
sucrose◼ Simple sugars join together to make complex
carbohydrates◼ Main function: serve as source of chemical
energy or fuel• Body utilizes this fuel to make ATP
MOLECULES OF LIFE⦿ Proteins◼ Made of chains of amino acids
• 20 common amino acids ● Peptides & polypeptides
◼ Form the structure of cells◼ Enzymes – catalyze specific biological
reactions◼ Others act as carriers – hemoglobin
MOLECULES OF LIFE
⦿ Lipids◼ Fats and oils◼ Do not dissolve well in water or blood
• Special proteins help carry lipids in the blood
◼ Not as big as proteins or carbs◼ Stored fat helps sustain prolonged exercise◼ Also helps during recovery from exercise ◼ Fatty acids, glycerides, phospholipids, steroids
CHECK YOUR UNDERSTANDING
⦿ What is the main function of carbs?⦿ What are the differences between simple and
complex carbs?⦿ What are the 3 functions of proteins in our
body?⦿ Why is it beneficial for our bodies to store
excess calories as fat?
NUCLEIC ACIDS⦿ Information carrying molecules in cells
◼ Two kinds found in cells: • Ribonucleic acid (RNA)• Deoxyribonucleic acid (DNA)
⦿ Subunits = nucleotides ⦿ Each made of a phosphate group, a sugar
group, and a nitrogenous base
NUCLEOTIDES⦿ 5 different kinds
◼ Adenine, guanine, cytosine, thymine, uracil
⦿ DNA is made of nucleotides containing ◼ A, G, C, T
⦿ RNA is made of nucleotides containing◼ A, G, C, U
DNA⦿ Two nucleotide chains coil
around each other to form a double helix
⦿ Base pairs◼ A & T, C & G
⦿ Base pairs are joined by hydrogen bonds ◼ DNA has ability to “unzip”
⦿ Sugar phosphate backbone are joined by covalent bonds◼ Stronger than hydrogen bonds
CHROMOSOMES ⦿ One DNA molecule and the proteins around it⦿ Almost every human cell has 46
◼ 23 from each parent
⦿ 22 pairs of similar chromosomes ◼ Plus one X Y pair in males◼ Two X chromosomes in females
⦿ 2 exceptions:◼ Sperm cells and egg cells (have 23)◼ Red blood cells – do not have nuclei or
chromosomes
RNA⦿ Polymer of nucleotides (like DNA)⦿ Base pairs
◼ A & U, C & G ⦿ 4 types
◼ mRNA• Information carrier in manufacture of proteins
◼ tRNA• Assists in manufacture of proteins
◼ rRNA• Forms ribosomes (large enzymes that act as catalysts
for protein synthesis)◼ Regulatory RNA
• Regulates which proteins are produced
CHECK YOUR UNDERSTANDING
⦿ What are nucleic acids?⦿ How do the nucleotides in DNA and RNA
differ?⦿ Why is it important that DNA has the ability
to “unzip”?⦿ How many chromosomes do most human cells
have?
ATP⦿ Adenosine triphosphate⦿ Composed of:
◼ adenine base, sugar, and three phosphate groups
⦿ Common energy source ⦿ Chemical potential energy is stored in bonds
between the phosphates
WATER⦿ All life is water based⦿ 2/3 of the mass of the human body⦿ Water forms hydrogen bonds⦿ Responsible for:
• High heat capacity• High boiling point• Solvent properties
BELL WORK⦿ Materials Needed: bell work notebook,
writing utensil, and A&P book. Turn in Lesson 2.1 homework.
⦿ Date?⦿ What is biochemistry? Why is it important in
the study of A&P?⦿ What kind of bonds join base pairs in DNA?
What do these bonds allow DNA to do?
CELLS⦿ Surrounded by extracellular fluid⦿ Plasma membrane
◼ Defines the outer shell of a cell ◼ Keeps the inside in and outside out◼ Controls what passes through
⦿ Cytoplasm◼ Inside the membrane◼ Contains everything except the nucleus
⦿ Cytoskleteton ◼ Defines the shape of the cell◼ Gives it mechanical strength
CELLS⦿ Mitochondria
◼ Make ATP◼ Universal carrier of energy within cells◼ “Powerhouse”
⦿ Golgi Apparatus◼ Set of membranous discs◼ Produces spheres called vesicles
• Vesicles deliver proteins to the plasma membrane
CELLS⦿ Ribosomes
◼ Very large enzymes • Made of RNA and proteins
⦿ Endoplasmic Reticulum◼ Network of membranes in the cytoplasm◼ Rough and smooth ER
• Rough – protein production and modification• Smooth – “replacement” membrane is made● Site of steroid hormone production in cells or
reproductive organs
LIFE CYCLE OF A CELL⦿ Interphase
◼ 3 subphases• Gap phase (G1)● Cell maintenance and growth
• Synthetic phase● DNA synthesis
• Gap phase (G2)● Cell maintenance, growth, and preparation for
division
⦿ Some cells will never divide (red blood cells in brain)◼ These cells are in phase G0
LIFE CYCLE OF A CELL⦿ Mitotic Phase
◼ Broken into mitosis and cytokinesis◼ Mitosis
• Division of a cell nucleus and chromosomes into two nuclei
◼ Cytokinesis• Division of the cytoplasm
⦿ Mitotic Cell Division◼ Process by which a single fertilized egg cell
develops into an adult made of trillions of cells
LIFE CYCLE OF A CELL⦿ Mitosis is broken down into 4 phases:
◼ Prophase• chromatin condenses to form chromosomes • Spindle fibers form
◼ Metaphase• Spindle fibers lock onto chromosomes and are
positioned along the midline of the cell
◼ Anaphase• Separase cuts each centromere in half – 46 chromatids
go to one side, 46 go to the other
◼ Telephase• Chromosomes decondense and a new nuclear
membrane forms around the DNA
HISTOLOGY ⦿ Study of tissues⦿ 4 main types of tissue
◼ Epithelial ◼ Connective◼ Muscle◼ Nervous
⦿ Each tissue has its own subtypes
EPITHELIAL TISSUE⦿ Includes epithelia and glands⦿ Epithelia
◼ Cover the body & line cavities within the body
⦿ Glands◼ Secrete chemicals to the outside world or within
the body
⦿ Epithelial tissue functions◼ Protect the body from physical damage◼ Control what substances enter and leave body◼ Provide sensory information◼ Secret various substances
EPITHELIAL TISSUE⦿ Classified according to layers and shape
CONNECTIVE TISSUE⦿ Found throughout the body
◼ Protects internal organs◼ Gives strength to resist external forces (gravity)◼ Maintains proper shape of organs◼ Provides framework on which muscle can pull
• Allows movement
⦿ 4 major classes◼ Connective tissue proper◼ Cartilage◼ Bone◼ Blood
LOOSE CONNECTIVE TISSUE
DENSE CONNECTIVE TISSUE
CARTILAGE
BONE
BLOOD
MUSCLE TISSUE
NERVE TISSUE
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